A multicentre comparative crossover study of benoxaprofen in the treatment of osteoarthritis was undertaken by general practitioners in the United Kingdom. Rheumatologists from 20 centres helped to coordinate the trial and provided x-ray confirmation of the diagnosis. In predetermined random order, patients were assigned to treatment groups and given either benoxaprofen or one of the comparator drugs (diclofenac, indomethacin, flurbiprofen, or piroxicam) for the first four weeks. Results from the first 1403 completed cases revealed that patients preferred benoxaprofen over all the comparator drugs.